JJ has been using 50/50 for his 70 bottle and 35/25 for his 120 bottle now
for a few years. Bill Mee has been using heliox, I have been using nitrox.
Bill Mee gets the cleanest results.

We have been trying to see what works best.

JJ and I played sports all our lives, I was a defensive back and JJ was a
linebacker at U of Florida. That takes a toll on the knees. JJ found that
when he used the 50/50, he had no symptoms of any kind in his knees, when he
used nitrox, they felt weird afterwards. My knees do not react to deco at
all, so I can not tell by that measure.

Bill Mee found that he was able to speed the deco severely by using all
heliox. I just do the same thing over and over as the baseline, so we can
see if it is the gas or the deco that is successful or unsuccessful.

The overall changing of the shape of deco and the gas choices were done by
myself and JJ through trial and error, and by watching what happened with
other team members.

Interestingly, even the most fit guys, like Bill Gavin, would get bent if
the used 30-40 oxygen bottles for 110-120 starting depth and then the
oxygen, whereas if they used 35, 50 and oxygen they did not get bent, so
that is how we got there. JJ and I found that using the trimix in the deeper
deco gases improved results massively. JJ and I also found that lowering the
oxygen in the bottom gas and boosting the helium made deco a lot faster and
cleaner, contrary to what the "theories" tell us.

In general, we found that helium is a wonder gas for solving the deco
problem.

-----Original Message-----
From: Don Hoover [mailto:Don.Hoover@da*.ne*]
Sent: Tuesday, February 26, 2002 9:05 PM
To: trey@ne*.co*
Subject: RE: Helium


George,

Has JJ been using 50/35 or 50/? for his 70ffw deco?

-----Original Message-----
From: George Irvine [mailto:girvine@be*.ne*]
Sent: Tuesday, January 29, 2002 7:44 AM
To: Wendell Grogan; Dean Laffan
Cc: quest@gu*.co*
Subject: RE: Helium


True, and it basically does what high ppo2 is "supposed" to do in terms of
shortening deco. We figured out a while back that helium was the correct
substitute for high ox , and that makes it a great choice for shallow dives
as well. The only problem is that it is expensive, and you would need a
booster pump to dive heliox unless you wanted to use lower final pressures
( which is what Bill Mee does ).

JJ and I have found that we seem to be getting pretty clean well before we
get to the shallow deco stops, and this may also be a contributing factor as
to why we can abbreviate the 40 stop on a long dive. JJ uses helium in his
70 foot bottle as well. I have been using nitrox, Bill Mee heliox. Mee has
the fastest out times.

-----Original Message-----
From: Wendell Grogan [mailto:wgrogan@dc*.ne*]
Sent: Monday, January 28, 2002 9:31 PM
To: Dean Laffan
Cc: quest@gu*.co*
Subject: Re: Helium


What this reminds me of is if you look back at the history of helium,
they originally proposed it as a non-deco gas.  The theory was that
since it went in and out of solution so quickly, your wouldn't need to
do any deco.  What WKPP may be showing us is that the theory was almost
right.  If you look back over the last couple of weeks, the feeling I
get from what Trey has been saying is that if you do the deep stops, let
the gas get out of the tissues without excessive bubbling at depth, then
you can basically blow off the shallow stops.
Wendell

Dean Laffan wrote:
>
> on 29/1/02 3:17 AM, Chris Elmore at elmorec@at*.ne* wrote:
>
> > Short answer: Helium also goes *into* tissues faster than nitrogen.
> > Longer answer: All gases seem to go into tissues faster than they come
out.
> SNIP
>
> HI Chris
>
> Isn't there also some question about the way Buhlman modelled He, that it
> wasn't properly allowed for in his calculations ?  Something about him
> extrapolating He half times from the N2 rather than actual emperical He
> tests ....  ?
>
> I guess the commercial sector is probably better versed in this area. No
> wonder George has been talking to guys like Bill Hamilton and Bruce W.
>
> Is it the also the case that most of the non VPM programs out there are
> still using Buhlmann B as a base algorithm and the in-water results (like
> the WKPP) and even other divers not using "George's" deco are suggesting
> that He is more "friendly" than the original Buhlman models would have us
> believe ?
>
> regards
>
> dean laffan
> real world productions
> melbourne, australia
> ph +613-9419-3966
> Mobile 0418-525-315
>
> --
>
> "The reasonable man adapts himself to the world. The unreasonable one
> persists in trying to adapt the world to himself. Therefore all progress
> depends on the unreasonable man."
>
>  - George Bernard Shaw.
>
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